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MULTIPLE CONTROL APPARATUS Original Filed Jan. 2, 1930 5 Sheets-Sheet 5mmw @www Q lim @M De@ E?, T935. H. A. THOMPSON l MULTIPLE CONTROLAPPARATUS Original Filed Jan. 2, 1930 5 Sheets-Sheet 4 ANN Dec 17, 1935.H. A, THoMPsoN MULTIPLE CONTROL APPARATUS Original Filed Jan. 2, 1930 y5Sheets-Sheet 5 INVENTOR: l-l. H1??? ompan,

Patented Dec. 17, 1935 UNITED STATES PATENT OFFICE MULTELE CONTROLAPPARATUS Application January 2, 1930, Serial No. 417,973 Renewed May 7,1935 18 Claims.

My invention relates to multiple control apparatus, and is particularlyadapted for, though not limited to, the control of the railway trackswitches and signals in a railway switching or interlocking layout.

One feature of my invention is the provision of means for controllingthe devices in each of various partly inter-inclusive groups by a singlemovable contact member in cooperation with a plurality of fixed contactmembers. Another feature of my invention is the provision ofinterlocking control for various groups of devices by means of slidingcontact members operated along intersecting guides.

I will describe one form of apparatus embodying my invention, and willthen point out the novel features thereof in claims.

The accompanying drawings, Figs. l to 1'7, inclusive, some of which arediagrammatic, illustrate one form of apparatus embodying my invention.Fig. l is a view illustrating a control panel for a railway switch andsignal layout which is shown diagrammatically in Fig. 8. Figs. 2 to 7,inclusive, are views showing portions of the apparatus of Fig. l. Figs.8 to 16, inclusive, are diagrammatic views showing means controlled bythe apparatus of Fig. 1 for controlling the switches and signals of Fig.8. Fig. 17 is a diagrammatic View showing indication means controlled bythe signals of Fig. 8 in association with parts of the apparatus shownin Fig. l2.

Similar reference characters refer to similar parts in each of theviews.

Reference characters in Figs. 8, 10, l1, and 13 to 16, inclusive, referto parts which are similar to parts designated by similar referencecharacters in Figs. l, and 6 to l1, inclusive, of my application forLetters Patent of the United States, Serial No. 416,061, filed Dec. 23,1929, for Multiple control apparatus.

Referring to Fig. 8, a stretch of double track railway is here shown,tracks ca; and bb of which are interconnected through crossover ee towhich they are respectively joined by switches H2 and H2a and arelikewise interconnected by cross-over ff to which they are respectivelyjoined by switches H3 and H3. Tracks aa and bb are also respectivelyjoined to passing sidings ce and dd by switches H4 and H1.

The reference character S, with distinguishing exponents, designatessignals which are placed adjacent the point-s A, B, C, D, E and F,respectively, and which, as here shown, are of the semaphore type.Signals S12, S1b and S1c are mounted on a common mast 549, and signals84a, S4b and S4c are mounted on a common mast 550. Signals S111, S13,S13, S2 and S3 govern eastbound traic moves, that is, moves which aremade over the stretch of track from left to right as shown in thedrawings, and signals S4a, S42, S46, S5 and S6 5 govern westbound trafcmoves, that is, moves which are made over the stretch of track fromright to left as shown in the drawings.

Between the group of eastbound signals and the group of westboundsignals, eleven different routes 1o may be established according to thepositions of the various switches. Over each of these routes, traiiiccan proceed in either direction, that is, from west to east or from eastto West. The arrangements of the switches for these various l5 routesare as given in the following table:

Route 1,-A to E, switches H2, H3, and H4 normal.

Route 2,--A to F, switches H2 and H3 normal, and H4 reversed.

Route 3,-A to D, switches H2 and H2a reversed, and H3a normal.

Route 4,-A to E, switches H2, H211, H3a and H3 reversed, and H4 normal.

Route 5,-A to F, switches H2, H211, H311, H3, and H4 reversed.

Route 6,-B to D, switches H1, H2a, and H3a normal.

Route 7,-B to E. switches H1, H211, and H4 normal, and H3a and H3reversed. 30

Route 8,--B to F, switches H1 and H2a normal, and H321, H3 and I-I4reversed.

Route 9,-C to D, switch H1 reversed, and switches H2"t and H3a normal.

Route 10,-C to E, switches H1, H3a, and H3 reversed, and H2a and H4normal.

Route 11,-C to F, switches H1, H33, H3 and H4 reversed, and H2a normal.

Referring now to Fig. 1, a control panel is here shown comprising aninsulating plate 51 mounted on a second insulating plate 58, a portionof which is shown in Figs. 2, 3, 6 and 7. Channels 66 are cut in plate58 according to an arrangement which is similar to, and whichconstitutes a diagram of, the track layout shown in Fig. 8. 4a Thejunctions of these channels 66 are designated by the reference characterH with distinguishing exponents, as shown in Fig. 8 for thecorresponding switches.

Diagrams of signals, designated by the reference character S withdistinguishing exponents similarly to the corresponding diagrams shownin Fig. 8, may be painted or otherwise suitably applied on the surfaceof plate 5l. Slots 61 are cut in plate 5l according to an arrangementwhich is the left of letters C, B and A and to the right of letters DEand F. In Fig. 6, a section is shown through a channel 66 and thecorresponding slot 61.V f

Fixed contact members, designated by the reference character e withdistinguishing exponents, are mounted in the control panel. Each ofthese members comprises two elements p which are located opposite eachother along one of the channels 65. Contact members e, acting incooperation with movable contact members, control the switches andsignals shown diagrammatically in Fig. 8. V

The contact members for controlling the signals are distinguishable byexponents for the reference character e comprising the letter S with anumber corresponding to the number in the exponent of the referencecharacter for the corresponding signal. For example, contact member c55controls signal S5, and contract member .254 controls signals S48, S4band S40.

Two members .e are employed for controlling each single switch, andthree member a are employed forV controlling the pair of switches ineach crossover. One of the members a for each single switch controlsoperations of the switch to its normal position, and is distinguishableby an exponent comprising the letter n and a number corresponding to thenumber in the exponent for the reference character for the correspondingswitch. VThe second member z for each single switch control operationsof the switch to its reverse position, and is distinguishable by anexponent comprising the letter r and the number in the exponent for thereference character for the corresponding switch. For example, themember a4 controls operations of switch H4 to its normal position, andthe member a4 controls operations of switch H4 to its reverse position.

Each of two of the members z for each crossover controls operations ofboth switches in the Y crossover to their normal position. These membersare distinguishable by an exponent comprising the letter n and theexponent for the reference character foreach of the switches in thecrossover, respectively. The third member z for Veach crossover controlsoperations of both switches in the crossover to their reverse position,and is distinguishable by an exponent comprising the letter 1' and thenumber in the exponents for the switches of the crossover.

Each element p of each member z, as shown in Figs. 5 and 5a, comprises aterminal 62 to which a iiat spring B3 it attached. In Fig. 7 is shown asection through elements p of member 23H. Each element p, as here shown,is rigidly attached to plate 58 adjacent a channel 66 by means of nuts64 and a Washer B5.

Each movable lcontact member which cooperates `with fixed contactmembers z for controlling the switches and signals comprises a flexibledevice, here shown as a chain, which slides in certain channels 66. Thechannels 66 serve as guides for the movement of the chains. Each ofthese chains consists of a plurality of main links 60, -See Figs. 1, 2,3, 4 and Llar-and end links (il)a and Elib connected together verticallywith respect to the control panel by pins (il so that the chain isilexible horizontally. A post 59 is rigidly fastened in end links'williL of each chain. By means of this post, the chain is manuallymovablealong certain channels 66 according to the route which theoperator desires to arrange. Each chain, When moved along correspondingchannels 66, connects one element p of each member a adjacent thesechannels with the other elementp of the same member z as the chainsucessively engages these members. The elements p of each member 2remain thus connected with each other until the chain is returned to thenormal position in Which the post 5&1 is adjacent one of the controlpanel and the chain shown to the left of letter A.

Fig. 3 is a View of the chain to the left of letter A and a portion ofplate 58 with plate 51 removed.

Figs. 4 and 4a comprise a plan and a side elevation view, respectively,of one of the links 60 of the control chains.

Fig. 6 is a sectional View of a portion of the control panel showing achannel E6 in plate 58 and the associated slot 61 in plate 51.

Referring again to Fig. 8, the reference characters I and la designatethe rails of track aa, and the reference characters 2 and 2a designatethe rails of track bb. These rails are divided by insulated joints 3 toform a plurality of track sections a-A, A-ii,i1'-y`7`, ij-E', B-mm,mm-G, G-D, and D-d. Each of thesetrack sections is supplied with currentby a battery 4 connected across the rails adjacent one end of thesection. A track relay, designated by the reference character T with adistinguishing exponent, is connected across the rails adjacent theopposite end of each track section. f

Each track section in which a switch is located will be referred tohereinafter as a detector section. Track sections a-A and d-D in therear of signals S1 and S4, respectively, will be referred to as approachtrack sections.

Each switch I-I is operated by a motor which is controlled bypole-changing contacts of a polarized switch control relay m as alreadyshown and described in my application for Letters Patent of the UnitedStates, Serial No. 416,061, filed Dec.

23, 1929, to which I have already referred in this 55 presentapplication. Polarized switch indication relays, designatedV by thereference character h, with distinguishing exponents corresponding tothe numbers in the exponents for the reference characters for theswitches, are controlled by the switches as also already shown anddescribed in my former patent application to which I have just referred.

For each switch indication relay h, there is a reverse indication relaydesignated by the reference character t with a distinguishing exponentand a normal indication relay designated by the reference character iwith a distinguishing exponent. The controls forrelays t and i aresimilar to those shown in my patent application, Serial No. 416,061,except that an additional contact is included in each circuit, as, forexample, contact 558:4 in the circuit for relay t and contact 551n4 inthe circuit for relay 114e.

erence characters PS1 and PS4, are controlled exlU5 which operatescontact 39115.

actly similarly to the relays designated by the same referencecharacters, respectively, in my former patent application, Serial No.416,061. Stick locking relays Q52, Q53, Q and Q56, and

' thermal relays N52, N53, N55 and N56 are also controlled exactlysimilarly to the relays designated by the same reference characters,respectively, in my former patent application referred to above.

. Relays X1a, to X511, inclusive, which enter into the controls forrelays P and Q in my present application, are, however, controlled in adifferent manner from relays X1 to X6, inclusive, which enter into thecontrols for relays P and Q in my former patent application.

Track relays T2 to T1, inclusive, slow-releasing relays I2 to I7,inclusive, and repeater relays U2 to U1, inclusive, are controlledexactly similarly to relays having corresponding reference characters,respectively, in my patent application, Serial No 416,061. The controlcircuits for these relays are therefore omitted from the drawings in mypresent application.

In each oi the drawings, the contacts operated by the various relays, orby time releases J, or by other control devices which will behereinafter described, are identied by numbers, such numbers havingdistinguishing exponents when such contacts are not shown adjacent therespective relay, release, or other device by which the contacts areoperated. The exponent for each of these contact numbers comprises thereference character and exponent of the respective relay, release, orother device. For example, the exponent U5 or contact 33115, shown inthe circuit for relay Q52 in Fig. 8, comprises the reference character Uand its exponent 5 for repeater relay Similarly, exponent m4 for contactlim1 in the control circuits for relay i and t comprises referencecharacter m and its exponent 4 for a switch control relay m4 whichoperates lllmi. Also exponent J51 for contact 5|5J51 in the circuits forsignals S1, shown in Fig. i6, comprises reference character J and itsexponent S1 for a time release .T51 which operates contact 5i5-151- InFig. 9, relays designated by the reference character n or r withdistinguishing exponents are shown controlled by the xed Contact membersa, for the normal and reverse control respectively, of the variousswitches, when the elements p of these contact members are bridged by alink 66 of one of the control chains shown in Figs. l, 2 and 3.

Referring to Fig. l0, route locking relays, each of which is designatedby the reference character V with a distinguishing exponent includingthe letter e, are controlled to prevent operation of the switches ineach route when an approach or stick locking relay P or Q,respectively', for the eastbound direction of the corresponding routehas been deenergized. Route locking relays, each of which is designatedby the letter V with an exponent including the letter w, are similarlycontrolled to prevent operation of 'the switches in each route when anapproach or stick locking relay I or Q, respectively, for the westbounddirection or the corresponding route has been deenergized.

In Fig. l1 are shown the circuits for polarized switch control relays mcontrolled by normal and reverse switch control relays n and 1*,respectively, of Fig. 9. Con-trol of relays m by either normal orreverse control relays n or r, respectively, is prevented when certaintrack repeater relays U or certain route locking relays V or certainapproach or stick locking relays P or Q, respectively, are de-energized.

Fig. 12 shows relays designated by the reference character 7c withdistinguishing exponents, each of which is controlled by a xed contactmember e for a signal when the elements p of such a contact member arebridged by a link 66 of one of the control chains. The exponents for thereference character k correspond with the numbers in the exponents forthe reference characters for the associated signals, respectively.

Each relay k controls a route relay designated by the referencecharacter Y with an exponent corresponding with that of the associatedrelay lc. Each relay Y is also controlled by normal and reverse switchcontrol relays n and r, respectively, for all the switches in each routewith which the relay Y is associated. Each route relay Y is alsocontrolled by a back contact of the route relay for movements in theopposite direction over the same route. In this Way, protection isprovided against trouble on account of a control chain contemporaneouslyclosing Contact members e for opposing signals.

Referring now to Fig. i3, route relays Y are here shown controllingsignal control relays each of which is designated by the referencecharacter X with an exponent which includes the exponent for theassociated relay Y. Each relay X is also controlled by a normal cr areverse indication relay z' or t, respectively, and by a normal or areverse svvitch control relay n or r, respectively, for each switch in aroute controlled by an associated signal, and hence all switches in agiven route must be in the proper position and the relays n and r forthe route must be energized before the relay X for that route can becomeenergized. Each relay X is also conrolled by a back contact of the relayX for the opposite traffic direction of the same route.

Signal stick relays are shown in Fig. le. Each of these relays isdesignated by the letter L with an exponent to indicate the signals withwhich itis associated, Each of these stick relays is controlled by theapproach locking relay P which is associated with the same signals, aswell as by repeater relays U for all tracks over which the signalsgovern.

Fig. 15 shows the control circuits for signal call-on relays, each ofwhich is designated by the reference character R with an exponent toindicate the signal with which it is associated. Each of these call-0nrelays is provided with a pickup circuit which is controlled by itscall-on push button K, and is provided with a stick circuit which iscontrolled by the signal control relay X for the same signal.

In Fig. 16 are shown the local control circuits for the various signalscontrolled by signal relays X. Signals S1 and S4 are also controlled bynormal or reverse indication relays for the switches in the routesgoverned by these signals.

In Fig. 17, an indication means shown as an electric lamp w iscontrolled by a relay o. Relay 'u is, in turn, controlled by contactsElli of relays Y in association with contacts S3, 94 and 95 Vwhich areoperated by signals S. Each of the cuit passing from terminal zr,through contact l Ving from terminal of ing my invention, I will nowexplain the operation of the apparatus.

As shown in the drawings, all parts are in their normal condition, thatis, each of the Ytrack sections shown in Fig. 8 is clear, each of thecontrol chains of Fig. 1 is in its normal position as. shown, eachswitch H is in its normal position, and each of the signals S isindicating stop. Since each of the track sections is clear, each of therelays T and U is energized, and each of the. relays I is de-energized.With each of the switches in its normal position, each of the polarizedindication relays h is energized in the normal direction.

With signals S1 indicating Vstop approach locking relay P51 is energizedby its circuit passa source of current not shown in the drawings,through contacts 2l, 22 and 23 operated by signals S16, S11o and S12,respectively, contact 24 of relay T1 in multiple with contact 55| ofrelay P51, contact 21x12, and the winding of relay P51 to terminal oI ofthe same source of current. Approach locking relay 125% is energized bya circuit which is -similar to that just traced for `relay P51.

With signal S2 indicating stop, stick locking relay Q52 is energized byits circuit passing from terminal x, throughrcontact 28 of signal S2contact 29x22, contact 33 of relay Q52 and the winding of relay Q52 toterminal o. Stick locking relays Q53, Q55 and Q56 are energized bycircuits which are similar, respectively, to the circuit just traced forrelay Q52 With all approach and stick locking relays P and Q energized,and with all track repeater relays U energized, all of the route lockingrelays VV are energized as shown in Fig. 1). For eX- ample, relay V21eis energized by a pick-up circuit passing from terminal cv, throughcontacts 559553, 565Q52 56IP511 563112, 56555, 566116, and the windingof relay V2ae to terminal o. A stick circuit ior relay V2ae is alsoclosed, which is the same as the pick-up circuit just traced as far ascontact 56IP5'1, and Vthence passing through contact 561 of relay V226,and the winding of relay V281e to terminal o'.

I will now assume that the operator in charge desires to arrange for atraffic movement over Route l, from A to E. He, therefore, takes hold ofthe post 59 ofthe chain shown to the left of letter A in Fig. 1, andpulls it to the right, causing links of the chain to bridge the elementsp of contact members 251, 2211, e211, and e411, succes- Vsivelyin theorder named.

When contact member 251 is closed by the bridging of its elements p bythe chain, relay k1,

Vshown in Fig. 12, becomes energized by its circuit passing fromterminalzr, through contact member e51, and the winding of relay k1 to terminalo. 1

Upon the closing of contact member e211, relay n2 shown in Fig. 9,becomes energized by its cirmember 2211, and the winding of relay 11.2to terminal o. Relay n2 upon becoming energized, closesits front contact559112J causing relaym2 shown in Fig. 11, tobe energized in the-normaldirection by its circuit passing from battery gg, through contacts590112, 5921731, 594121, 5951721?,

' 596151, 597112, 595126, and the Winding of relay m2 to, terminal 44Iwhich is common to batteries gg and hh., and thence back to battery gg.Since switches H2 and H2"1 are already in their normal positionfnomovement of these switches is produced by the energization of relay m2as just traced. Upon the closing of contacts 2311 and e411, relays 11.3and n4 are energized similarly to relay n2 as already described, andrelaysV m3 and l m4 are therefore energized in the normal direc- L5Vtion by their circuits passing through front contacts 599113 and 6I4114,which are similar to theV circuit previously traced for relay m2.

When relays k1, n2, n3 and n4 are all energized,

a circuit is completed for relay Y1, shown in Fig. 1() l2, passing fromterminal m, through contacts 622115, 623114, 633113, 634112, 635 ofrelay k1, and the Winding of relay Y1 to terminal 0. Relay Y1 becomingthus energized, opens its contact 64IY1, thus preventing the possibilityof relay Y5 be- 1X5- coming energized by its circuit through contact 649of relay lc5.

When relay Y1 becomes energized, a circuit is completed for relay 'upassing from terminal through contact 93510, terminal e, contacts 9451112,0.my and 945121, front contact 96111, and the winding of relay v toterminal o. Lamp w then becomes lighted by its circuit passing fromterminala, through contact SI of relay v, `and lamp w to terminal o. 2.?

When relay n4 becomes energized, normal indication relay i421 becomesenergized by its circuit passing from battery I3, through normal contact|4514, contact 551114, contacts I5 and I6 of relay h4, contact I1 ofrelay i411, and the Winding 3,0l of relay i411 back to battery I3.Relays i211 and i311 and energized by similar circuits when relays n2and n3 become energized.

With relay Y1 energized, a circuit is then comi pleted for relay X111,shown in Fig. 13, passing 3,5; from terminal 11:, through contact k616of relay X511, back contact 611115, contacts 6181411, 61911", 61H32,670113, 669122, 668112, front contact 663111, and the winding of relayX1a to terminal o.

Relay i211 upon becoming energized causes relay L51 to become energizedby its circuit passing from terminal m, through contacts 43121, 44113,U4, 46112, 41151, and the winding of relay L51 to terminal o. Relay L51upon becoming energized closes its stick circuit which includes its own45 contact 48 instead of contact 41151 in the pick-up circuit justtraced. Y

Relay X111 upon becoming energized completes an operating circuit forsignal S111 passing from terminal cc, through contacts 5I4X1a, 5I 5-151,5I612, 50v 5II14, 5I8L51, contact 5I9 operated by signal S111, and themechanism of signal S11 to terminala. The arm of signal S1a thereforemoves to its proceed position, breaking, at its contact 23, the pick-upand stick circuits already traced for relay P51. Relay P51 is therebyde-energized, and hence opens its contact 56-IP51 in the circuitsalready traced for relay V215. Relay 112 is now energized, however, andhence its contact 5621211 is closed, forming a branch path aroundcontact 56IP51 and hence relay V2ae continuedfenergized. Relay P51 uponbecoming deenergized .also opens its contact 51 IP51 in the circuits forrelay V36, and since relay t2a is de-energized, relay V3e now becomesde-energized. On O5 account of relay P51 being de-energized, the cir#cuit already traced for relay m2 is open at contact 5961'51. The normalcontrol circuits for relays m3 and m4 are open at contacts 6021132 and6I5V3e, respectively. 70

The arm of signal S111, upon leaving its stop position, also opens itscontact 94512, causing relay v to be de-energzed and so causing lamp wto be extinguished. The operator is thus informed that the switches inthe route are in the '(5 -positions required for the route, and that thearm of signal S1a has left its stop position.

An eastbound train approaching signal S1, after the route from A to Ehas been arranged as just described, de-energizes approach track relayT1 which then opens its contact 24 in the pick-up circuit already tracedfor relay P51 which, however, is already open at contact 23 of signalS12. When the train passes signal S12, entering section A-ii, relay T2and, in turn, relay U2 becomes de-energized, and relay I2 becomesenergized. Relay U2, upon becoming de-energized, opens its contact515112 in a pick-up cir-- cuit for relay V3e which, however', is alreadydeenergized as previously described, and also opens its contact 591112in the circuit traced for relay m2. Relay U2, upon becomingde-energized, ,also opens its contact 46112 in the circuit for relayL51, causing relay L51 to become de-energized. Relay L51, upon becomingde-energized, opens its contact 5| 81151 in the circuit already tracedfor signal S12 and so causes the arm of signal S12 to return to its stopposition.

With the arm of signal S11 again in its stop position, relay v is againenergized by its circuit previously traced, causing lamp w to againbecome lighted. The operator is therefore informed that a train ispassing signal S12.

I1" now the operator returns the control chain for the route from A to Eto its normal position to the left of letter A of Fig. l, he willde-energize relays n4, n3, n2 and k1 in the order just named. Relay Y1and, in turn, relay X1a therefore become de-energized. Front contacts598m, 599113 and 5415114 are opened in the circuits for relays m2, m3and m4 respectively, which, however, have already been broken by relaysP51 and We as already described. With relay X12 deenergized, and withthe arm of signal S12 now again in its stop position, and with relay U2de-energized, .a second pick-up circuit is completed for relay P51passing from terminal x, through contacts 2i, 22 and 23 of signals S1,S11 and S12, respectively, contact 26 of relay U2, contact 27x12, andthe winding of relay P51 to terminal o.

With relay Y1 de-energized, front contact 96Y1 is open, ,and hence relayu is again de-energized and lamp w is therefore extinguished.

As long as the train remains in section A-z'i, the pick-up circuit forrelay V3e continues open at contact 51512, and when the train hasentered section ii-jj and has left section A-z'i, relay V3e, on accountof contact 51153 being open, remains cle-energized although relay U2closes its Contact 515112. When the train moves out of section ii-y'y',relay U3 again becomes energized and hence relay V3e becomes energizedby its pickup circuit passing from terminal through contacts 5'HP51,5B1/32e, 575112, 511113, and the Winding of relay VSe to terminal o.Relay Ve, upon becoming energized, completes its stick circuit whichfollows the path `iust traced as far as contact 5131/328, thence throughcontacts 518 of relay V32, and the winding of relay V3'3 to terminal o.When the train leaves section ii-E, all parts of the apparatus willtherefore again be in the normal condition.

if, after a route has been arranged for a move such as from A to E aspreviously described, a train has entered the route, causing lamp w tobe lighted as already traced, and the operator then desires to provide acall-cn signal indication to authorize a second train to enter the routewhile it is still occupied by the first train, he will, while the chainis still bridging contact elements 251, Z211, e3 and e411, depress pushbutton K51 sho-wn adjacent signal S1, With push button K51 depressed,call-on relay R51, shown in Fig. 15, becomes energized by its circuitpassing from terminal I through Contact 565151, and the winding of relayR51 to terminal o. Relay R51, upon becoming energized, completes itsstick circuit passing from terminal rc, through contact 5315x121,contact 508 of relay R51, and the winding or" relay R51 to terminal 10o. Relay R51 will therefore continue energized by i its stick circuit aslong as relay X1a continues energized although the operator ceases todepress push button E51. With relay R51 energized, a circuit is nowcompleted for signal S1c passing 15 from terminal through contacts5MX12, 5|5J51, blme, i'im, 525551, 528 oi signal S12, 529 ofsignal S12,the mechanism of signal S1C to terminal o. The arm of signal S1cthereupon moves to its proceed position, breaking at its contact 93510,20 the circuit previously traced for relay v. Relay o then opens itscontact Sil, extinguishing lamp w.

Since the circuit just traced for signal S1c does not include any traiccontrolled relay contacts, the arm of signal S1C will continue toindicate procoed until the operator returns the control chain toward itsnormal position.

When the operator is returning the control chain toward its normalposition, relay Y1 becomes de-energized as soon as relay n4 opens itscontact 523114. Relay Y1 then completes, at its back contact 96Y1, asecond circuit for relay v, passing from terminal x, through contact9351, terminal f, back contact $5121 and the winding of relay o toterminal oi. Relay u then again closes 35 its contact Si, causing lamp wto again become lighted.

When the operator is returning the control chain toward its normalposition, relay X12 also becomes cle-energized as soon as relay n4 opensits 40 contact 529114, and hence relay X12 opens its Contact 5652512,causing the arm of signal S1c to return to its stop position before theoperator has completed the return of the control chain to its normalposition. When the arm of signal 45 S1c leave its proceed position,contact 93510 opens, causing relay o to again be de-energized and hencelamp w to become extinguished. The operator is thereby informed that thearm of signal S1c has responded to his movement of the con- 50 trolchain. The arm of any of the other signals shown in Fig. 8 is similarlyreturned to its stop position when a corresponding control chain isreturned toward its normal position.

I will now assume that with all parts of the 55 apparatus again in thenormal condition as previously described, the operator arranges Route lfor a move from A to E and clears signal S12, as previously traced, bymoving the control chain along the guides in the control panelcorresponding with the route A to E. If, now, after an eastbound trainenters section a-A, de-energizing relay T1, the operator should desireto send the train over some other route than Route l, he will return thecontrol chain toward its normal position far enough to permit thecontrol chain to be moved along the channels 66 corresponding to thedesired route, and so causing relay X12 to become de-energized and thearm of signal S12 to move to the stop position.

On account of relay T1 being de-energized due to the presence of a trainin section -A, relay P51 does not pick up when relay X1a closes itscontact 21x12 and the arm of signal S12, returning to its stop position,closes its contact 23. 7l

Inorder to energize relay PS1, the operator will Vbecome energized by athird pickup circuit passing from terminal through contacts 2|, 22 and23 of signals S10, S111 and S111, respectively, contact 25 of releaseJS1, contact 21x13, and the winding of relay PS1 to terminal o.Y RelayPS1, upon becoming energized, completes its stick circuit through itscontact 55|, and hence the 0perator will now return release Jsl to itsnormal position. kRelay PS1 being energized causes relay V3e to againbecome energized. The operator'can then energize relays m for theswitches 0f any other route by moving the control chain alongcorresponding channels 66 in the control panel.

Assuming that the operator wishes to send the train, which has arrivedin section a-A, over Route 2 from A to F, he will so move the controlchain that contact members esl, 2211, e311 and e411 are closed, causingrelays k1, h2, h3 and r1 to be energized. Relays'm2 and m3 will nowagain be energized in the normal direction by the closing of frontcontacts 599112 and 599113, respectively. Relay 'm4 will be energized inthe reverse direction by its circuit passing from battery hh, throughterminal 44|, winding of relay m4, and contacts 6|9U1, 6|8QS6, 6|1QS5,6|6V3e, back contact 6|4111,

and contact 6|5f4 back to battery hh, relays i211,

andi will now'be energized as previously described, and relay 1513 Will,when switch H1 has been moved toits reverse position in response to thereverse energization of relay m4, be energized by its circuit passingfrom battery i3, through reverse contact |4214, contact 55814, contacts|8 Vand I9 of relay h4, contact 26 of relay i111, and the winding ofrelay i411 back to battery |3.

Upon the energization of relay r4, a second circuit is completed forrelay Y1 passing from terminal r, through contacts 624116, 625, 633113,642112,

635 of relay k1, and the Winding of relay Y1 to terminal o. Relay i411upon becoming energized then completes a second circuit for relay X1apassing from terminal a3, through contact 686 of relay X62, back contact68|Y6, contacts 682143, 68314, 61|133, 616113, 669121, 663112, irontcontact 663111, and the winding of relay Xla to terminal o. Y

Relay Y1, upon becoming energized, again completes the circuit rsttraced for relay o, which then causes lamp w to again become lighted.

With relay X111 energized, the arm of signal S1c becomes operated to itsproceed position by its circuit passing from terminal rc, throughcontacts 5| 411111, 5|5JS1, 5|612a, 5251, 528 of signal S111, 529 ofsignal S11, and the mechanism of signal S1c t0 terminal o. When the armof signal S11 leaves its stop position, approach locking relay PS1becomes j deenergized by the opening of contact 2| of signal S12.

The arm of signal S1, upon leaving its stop position, opens, at itscontact 93510, the circuit for relay U, causing relay o to becomede-energized,

and this relay, in turn, causing lamp w to become extinguished.

When the operator later, in arranging another route,Y moves a controlchain to close. contact member e411, switch H1 will be returned to itsnormal position due to the energization of relay n4 by member e411,which causes relay m1 to be i energized in the normal direction.

Assuming now that all parts of the apparatus are again in the normalcondition, and that the operator desires to arrange for a trafficmovement n, over Route 3 from A to D, he will move the conl0 trol chainfrom its position to the left of letter A to bridge contact members 251,z2' and 23211 in the order named. Relays k1, r2 and n3 will thereforebecome energized. Relay m2'wil1 now be supplied with current of reversepolarity by its circuit passing from battery hh, through contact 59H2,and back contact 599112, and thence through the circuit previouslytraced from contact 590112 to terminal 44| for relay m2, and back tobattery hh. Relay m3 will be again energized in the normal 20 directionby its circuit through contact 599113. With relays m2 energized in thereverse direction, switches H2 and H22 will be operated to their reversepositions. Relay h2 will then be energized ,g in its reverse direction,and relay i211 will then 25 become energized. Y

VRelay Y1 will now be energized by a third clrcuit passing from terminalal, through contacts 626134, 62 |113, 63212, 635 of relay k1, and theWinding M of relay Y1 to terminal o. Relay t211, upon becom- 30 ingenergized, then completes, at its contact 665123,

a third circuit for relay X1a passing from terminal x, through contact612 of relay X43, backrcontact 61324, contacts 6141311, 615113, 665123,66412, front cons tact 663111, and the Winding of relay X12 to ter- 35minal o. The energization of relay Y1 causes lamp w to be lighted aspreviously described. With relay 1522 energized, relay LS1 is energizedby its circuit passing from terminal 1:, through contacts 40122,'4 |116,42111, 46112, 41PS1, and the wind- 40 ing of relay LS1 to terminal o.When relay X1n becomes energized, signal S11u becomes operated to Y itsproceed position by its circuit passing from condition, and that theoperator Wishes to send 55 Va train by Route 4 from A to E. He thereforemoves the chain from letter A to bridge contact members e151, 221, 231and e411. Relays k1, r2, r3 and h1 therefore become energized, SwitchesH2, H23,V

H3a1 and H3 then move to their reverse positions, 60 Y and relays i211and t3a become energized as already described in connection withswitches H2 and H211. Relay Y1 is now energized by a fourth circuit passing from terminal zc, through contacts 622135, 623114,?` 62613, 63212,635 of relay k1, and the winding of relay Y1 to terminal o. Relay X1E1then, upon the energization of relays t211 and t311, becomes energizedby a fourth circuit passing from terminal, through contact 616 of relayX52, back contact `'Ill 611115, contacts 613113, 619114, 661131, 66613,66512a 66412, front contact 663111, and the winding of relay X1a toterminal o. The arm of signal S1c is then operated to its proceedposition bya cir... cuit passing from terminal a', through contactsV 755|4X'12, 515251, 520122, 524m, 528' of signal S12, 529 of signal S111,and the mechanism of signal S1c to terminal o. By the operation of theapparatus to clear signal S10, and the subsequent clearing of signalS10, lamp w becomes lighted and then extinguished as previouslydescribed.

Relay PS1 becomes de-energized upon the opening of contact 2| of signalSlc when the arm of this signal leaves its stop position. Upon thede-energization of relay PS1, relay V2ae becomes de-energized due to theopening of contact 56 IPS1 while contact 56212 is open. Relay V226, uponbecoming de-energized, opens its contact 56812ae, thereby de-energizingrelay V322. Relay V329, upon becoming de-energized, opens its contact513V3ae, causing relay V3E to be de-energized, contact 514132 beingalready open. With relay PS1 Cle-energized, relay m2 is de-energized asalready described, and with relay V3e de-energized, relays m3 and m4 arede-energized due to the opening of contacts 502132 and 6161138,respectively.

I will now assume that all parts of the apparatus are again in thenormal condition, and that the operator desires to arrange for a trafcmovement over Route 6 from B to D. He therefore moves, to the right, thechain which is shown in Fig. l to the left of letter B. By this means,he bridges contact members cs2, 2111, 22211 and 23211, causing relaysk2, n1, n2 and n3 to be energized and relays m1, m2 and m2 to beenergized by current of normal polarity. When switches H1, H22 and H32are in their normal position or have been operated to the normalposition as controlled by relays m1, m2 and m2, relays i12 22 and 1'32will become energized after relaysh1, h2 and h3 have been energized inthe normal direction as previously described for relay h4.

With relays n1, n2 and n3 energized, relay Y2 is energized by itscircuit passing from terminal through contacts $23124, 62H12, 627112,63cm, 633| of relay k2, and the winding of relay Y2 to terminal o. RelayY2 then completes a third circuit for relay '0, passing from terminalthroughv contact 9352, terminal e, front contact 95122, and the windingof relay o to terminal o. Relay v then closes its contact 91, causinglamp w to be lighted. When relay Y2 becomes energized, relay X22 becomesenergized by its circuit passing from terminal fr, through contact 612of relay Xla, back contact 673114, contacts $14132, 615113, 66l121,660112, 659112, 658111, front contact S51Y2, and the winding of relayX22 to terminal o. With relay X22 energized, the arm of signal S2 isoperated to the proceed position by its circuit which is controlled bycontact 5|3X22. The arm of signal S2, when leaving its stop position,opens its contact 9352 in the third circuit for relay o which thencauses lamp w to become extinguished.

When the arm of signal S2 leaves its stop position, stick locking relayQS2 becomes de-energized by the opening of contact 28 oi signal S2. If atrain now passes signal S2 into section B-mm, relay T5 and, in turn,relay U5 will become de-energized, and relay I5 will become energized.If, now, the operator returns the control chain toward its normalposition, relay Y2 will become ele-energized, completing a fourthcircuit for relay 1J, passing from terminal through contact 9352,terminal f, back Contact 96122, and the winding of relay v to terminalo. Lamp w will then become lighted. Relay X22 will also be de-energized,by this movement of the control chain, causing the arm of signal S2 toreturn to its stop position. The arm of signal S2, upon leaving itsproceed position, will open its contact S322, de-energizing relay u, andso extinguishing lamp w. Relay Q52 will be again energized by itspick-up circuit passing from terminal through contact 23 of signal '5S2, contacts 251122, and 39115, and the winding of relay Q52 to terminalo.

If, on the other hand, before a train passes signal S2, the operatorshould desire to arrange some other route which would conflict with the10 route from B tolj, he will likewise rst return the arm of signal S2to its stop position by returning the control chain toward its normalp-osition. With the arm of signal S2 again in its normal position, andwith relay X2a de-energized, 1-5 winding 3l of thermal relay NS2 willbecome energized by its circuit passing from terminal through contact 26of signal S2,'contact 29x22, winding 3l of relay NS2, and contact 34 ofrelay Q52 to terminal o. Upon the lapse of a given pe- 20 riod of time,relay NS2 will close its contact 32, causing relay QS2 to becomeenergized by a second pick-up circuit passing from terminal throughcontact 28 of signal S2, contact 29x22, contact 32 of relay NS2, and thewinding of relay 25 Q52 to terminal o. With relay Q52 now energized, theoperator can arrange any other route which he may desire.

I have described, for a few typical tralc movements, the operation ofthe apparatus em- 30 bodying my invention. From these descriptions andfrom the preceding general description, the operation of the apparatusfor every other possible traric movement will be readily understood uponreference to the drawings.

It will be clear that with apparatus embodying my invention, an operatorin chargeiof the apparatus, in order to arrange any route and clear thesignal for a given direction of traic through the route, has only tomove a corresponding con- 40 trol chain of Fig. l along the guides shownas channels 56 corresponding to the route. When the operator afterwarddesires to restore the control apparatus for the route to the normalcondition, he will return the chain to its normal posi- 45 tion. The armof the signal for the route will at once return to its stop position,and, when all the track sections are again clear, the approach or sticklocking relay for the route, and the route locking relays for `the routewill become energized. 50 The switches in the route will, however,remain in the positionsto which they were previously operated forarranging the route.

It will also be clear that, due to interconnecting guides whichcorrespond to they routes shown by 55 the track layout in Fig, 8, when acontrol chain is in a position for arranging the switches for a givenroute, no other control chain can be moved into a position for arranginga route which would conflict with the given route. In this way, inter-60 locking between routes is provided.

It follows that with apparatus embodying my invention, the control panelshown in Fig. l performs the functions of an interlocking machine and ofthe track model which is usually provided 65 for the information of theoperator.

The arrangement shown in Fig. 17 provides means comprising a singleindicator, which may be an electric lamp as here shown, or may be oi'any other suitable type such, for example, as an 70 electric bell, toindicate to the operator when the traflic governing devices associatedin any given route fail to complete their response to a correspondingmovement of a control chain.

As has been described, my invention provides 75 approach or sticklocking, detector track circuit locking, route locking, and signalindication locking for all switches.

Although I have herein shown and described only one form of multiplecontrol apparatus embodying my invention, it is understood that variouschanges and modifications may be made therein within the scope of theappended claims without departing from the spirit and scope of myinvention.

Having thus described my invention, what I claim is:

l. In combination, a plurality of railway tracks inter-connected bymeans of a plurality of switches to form a plurality or routes, a signaladjacent each end of each route for governing traine movements throughthe route in opposite directions, a diagram having a path correspondingto each of said routes, a switch contact member adjacent each said pathfor each switch of its route, a signal contact member adjacent each saidpath for each signal for the corresponding route, Contact means movablein each direction along each said path for closing the contact membersadjacent the path, means controlled by each said switch contact memberfor controlling an operation of its switch tothe position in which theswitch is included in the corresponding route, and means controlled byeach said signal contact member for controlling its signal when acontact .leans is moved Valong the corresponding path in the directioncorresponding to the direction of traine movements controlled by saidsignal.

2. In combination, a plurality of railway tracks inter-connected bymeans of a plurality of switches to form a plurality of routes, a signaladjacent each end of each routefor governing traic movements through theroute'in opposite directions, a manually operable device for each switchfor controlling an operation of the switch to its normal position, asecond manually operable device for each switch for controlling anoperation of the switch to its reverse position, a

route relay for each route, a second route relay for each route, controlmeans for each said first route relay controlled independently of thetrack switches by one of said manuallyV operable devices for each switchin its route and by a back contact of the second route relay for thesame route, control means for each said .second route relay controlledindependently of the track switches by one of said manually operable`devices for each switch in its route and by a back Contact of the firstroute relay for the same route, means controlled by each said firstroute relay and by each switch of its route for controlling the signaladjacent one end of its route, and means controlled by the second routerelay for the same route and by each switch of said route forcontrolling the signal adjacent the opposite end of the route.

3. In combination, a railway track switch, a manually operable device, asecond manually operable device, a polarized control relay for said yswitch energized in the normal or the reverse direction according assaid first or said second 4device is operated, a polarized indicationrelay energized in the normal or the reverse direction according as saidswitch is in its normal or its reverse position, a normal indicationmeans, a reverse indication means, means controlled by -Y said rstmanually operable device and by normal contacts of said polarizedindication and control relays for controlling said normal indication fVmeans, and means controlled by said second manually operabledevice andby-reverseA contacts of said polarized indication and control relays forcontrolling said reverse indication means.

4. In combination, a plurality of partly interinclusive groups ofrailwayl traffic governing devices, a manually operable device for eachof said groups, ymeans controlled by each said manually operable devicefor controlling its group of said traiiic governing devices, anindication means,

and means controlled by each said manually op- Y erable device forcontrolling said indication means when the condition of its group oftraffic governing devices does not correspond to the condition of saidmanually operable device.

5. Railway control apparatus comprising a,

panel having representations thereon of a plurality of railway tracksinterconnected by a plural-V ity of switches, a normal and a reversecontact element adjacent the representation of each of said switches, aplurality of movable contact elegfments manually controllable to movealong said representations of railway tracks for making contact withsaid normal and reverse contact elements, a normal circuit for eachswitch including the associated normal contact element and one u of saidmovable contact elements, a reverse ciri cuit for each switch includingthe associated reverse contact element and one of said movable Contactelements, and means controlled by each normal and reverse circuit foroperatingthe associated switch to normal and reverse positionsrespective1y. 5

6. Railway control apparatus comprising a panel having representationsthereon of a plurality or railway tracks interconnected by a pluy tactelements and one of said movable contactA elements for causing operationof the associated signal, and means controlled by each such signalcontrol circuit for preventing operation of the opposing signal for thesame route.

7. Railway control apparatus comprising a' panel having representationsthereon of a plurality of railway tracks interconnected by a pluralityof switches for forming a plurality of routes, a plurality of signalsfor governing trafficmd` movements in opposite directions over saidplu-fr rality of routes, a signal control element adjacent each end ofeach oi" said track representations, -a plurality of movable controlelements manually controllable to move along said track representationsfor engaging said signal control elements, and means controlled by eachsignal control element through engagement with a movable control elementfor causing a corresponding signal to be clearedY and for preventing thecontrol of a second signal by the same movable control element.

8. Railway control apparatus comprising a panel having representationsthereon of a plurality of railway traiiic governing devices, a controlelement mounted on said panel for each oi? lable to move along saidpanel for engaging eachV of said control elements, and interlocked meanscontrolled by each said movable element through engagement with certainof said control elements including the one f or the traine governingdevice associated with such movable element for causing the operation ofsuch device, said means including means for preventing the operation ofthe traflic governing device associated with the other mov-able element.

9. In combination, a railway track switch, a manually operable device, asecond manually operable device, a polarized control relay for saidswitch controlled by said manually operable devices to be energized inthe normal or the reverse direction according as said irst or saidsecond device is operated, a polarized indication relay energized in thenormalA or the reverse direction according as said switch is in itsnormal or its reverse position, a normal indication relay, a reverseindication relay, a circuit controlled by said first manually operabledevice and by normal contacts of said polarized indication and controlrelays for energizing said normal indication relay, a second circuitcontrolled by said second manually operable device and by reversecontacts of said polarized indication and control relays for energizingsaid reverse indication relay, and indication means controlled by saidnormal and reverse indication relays.

10. In combination, a railway track switch, a normal switch relay, areverse switch relay, a

lmanually controlled circuit for each of said switch relays forenergizing the corresponding switch relay, a normal and a reverseoperating circuit controlled by said normal and reverse switch relaysfor causing said switch to be operated to its normal and reversepositions respectively, a polarized indication relay energized in thenormal or the reverse direction according as said switch is in itsnormal or its reverse position, -a normal indication rel-ay, a reverseindication relay, a circuit including a front contact of said normalswitch relay and a normal contact of said polarized indication relay forenergized s-aid normal indication relay, a second circuit including afront contact of said reverse switch relay and a reverse contact of saidpolarized indication relay for energizing said reverse indication relay,and indication means controlled by said normal and reverse indicationrelays.

11. In combination, a plurality of railway tracks interconnected byswitches to form a plurality of partly interinclusive railway routes, asignal for each direction of traiiic movements over each of said routes,a normal and a reverse manual control contact for each of said switches,means controlled by the normal and reverse manual control contacts foreach switch for operating the switch to normal and reverse positionsrespectively, a manu-ally controllable signal control contact for eachsignal, a route relay for each signal, one or more circuits forcontrolling each route relay each of which circuits is controlled by thesignal control contact for the corresponding signal and by the normal orthe reverse manual control contact for each switch in a correspendingroute governed by the signal as well as controlled by a back contact ofthe route relay for the opposing signal for the same route, a signalcontrol relay for each signal, one or more circuits for controlling eachsignal control relay each of which circuits is controlled by a frontContact of the route relay for the signal and by the normal or thereverse manual control contact for each switch in a corresponding routegoverned by the signal as well as controlled by a back contact of thesignal control relay for the opposing signal for the same route, andmeans controlled by each sign-al control relay :for clearing thecorresponding signal. 5

l2. In combination, a plurality of railway tracks interconnected byswitches to form a plurality of partly interinclusive railway routes, asignal for each .direction of trane movements over each oi said routes,a normal and a reverse .10 manual control contact for each of saidswitches, means controlled by the normal and reverse manual cor 4rolcontacts for each switch for operating the switch tc normal and reversepositions respectively, a manually controllable signal control 15contact for each signal, a route relay for each signal, one or morecircuits for controlling each route relay each oi which circuits iscontrolled by the signal control contact for the corresponding signaland by the normal or the reverse man- `2Q ual control ccntact for eachswitch in -a correspending route governed the signal as well ascontrolled by a back contact of the route relay for the opposing signalfor the same route, a signal control relay for each signal, one or more25 circuits for controlling each signal control relay cach of whichcircuits is controlled by a front Contact of the route relay for thesignal and by each switch in the normal or the reverse position in acorresponding route governed by the signal 3o as well as by the normalor the reverse control Contact for each switch in the same route, andmeans controlled by each signal control relay for clearing thecorresponding signal.

13. In combination, a plurality of railway 35 tracks interconnected byswitches to form a plurality of partly interinclusive railway routes,

a signal for each direction of traic movements over each oi said routes,a normal switch control contact and a reverse switch control contact 40for each of said switches, means controlled by the normal and reverseswitch control contacts for each switch for operating the switch tonormal and reverse positions respectively, a manually controllablesignal control contact for each 45 signal, a route relay for eachsignal, one or more circuits for controlling each route relay eachincluding contacts which become closed when the signal control contacttor the corresponding signal is operated and other contacts which become50 closed when the normal or the reverse switch control contacts foreach of the switches of the route corresponding to said signal areoperated to establish said route, each said circuit also including aback contact of the route relay for 55 the opposing signal for the saineroute, and a signal relay controlled by each route relay for clearingthe corresponding signal.

14. In combination, a plurality of railway tracks interconnected byswitches to form a 60 plurality of partly inter-inclusive railwayroutes,

a signal for each direction of trac movements over each of said routes,a normal control relay and a reverse control relay for each of saidswitches, manually controllable circuits for en- 55 ergizing each ofsaid control relays, means controlled by the normal and reverse controlrelays for each switch for operating the corresponding switch to thenormal and the reverse position respectively, a manually controllablesignal 70 control contact for each signal, a route relay for eachsignal, one or more circuits for energizing each route relay includingone for route over which traine movements are governed by the associatedsignal, each of said circuits in- 75 cluding front contacts of thenormal or the reverse control relay for each switch in the correspending route, and contacts controlled by the signal control contactfor said signal, and a signal relay controlled by each route relay forclearing the corresponding signal.

respectively, to select a route, a route relay for each signal, acontrol circuit for each route relay independent of the track switchesbut including contacts of one of said manually controllable relays foreach switch of the selected route and a back contact of the route relayfor the signal adjacent the opposite end of the selected route, andmeans controlled by each route relay and by each switch of the selectedroute for controlling the corresponding signal.

16. In combination, a plurality of railway tracks inter-connected bymeans ofV a plurality of switches to form a plurality of routes, asignal adjacent each end of each route for governing traffic movementsthrough the routeV in opposite directions, manually controllable meansfor each switch forcontrolling anV operation of the switch to its normalor reverse position, respectively, to

Yselect a route, a route relay for each signal, Vcontrol means for eachroute relay controlled independently of the track switch by the manuallycontrollable means for each switch of the selected route and by a backcontact of the route relay for the signal adjacent the opposite end ofthe selected route, and means controlled by each route relay and by eachswitch of the selected route for Controlling the corresponding signal.

17. In combination with a track switch having two positions, two controlrelays, including one for each position of the switch, two indicationrelays, including one for each position of the switch, meanseffectivewhen a control relay becomes energized for moving the switch to acorresponding position, means elective only when a control relay isenergized and the switch occupies said corresponding position forenergizing the corresponding indication relay, and means controlled bytrack conditions and by said indication relays for governing trafc overthe switch.

18. Railway control apparatus comprising a panel having representationsthereon of a plurality of track switches and of twowopposing signals forgoverning the movement of trailic in opposite directions over theswitches, a control element mounted on saidv panel for each switch andsignal, a movable element for each signal manually controllable to movealong said panel to engage said control elements, and interlocked meanscontrolled by each movable element through engagement with the controlelements for each of said switches and for the corresponding signal forclearing such signal, and means controlled by said interlocked meansfor-preventing the clearing -of the opposing signal in Vresponse to theengagement of a movable ele-

